Endocrine Abstracts

Background: The 2017 World Health Organization classification of pituitary tumors established that, pituicytoma, granular cell tumor of the sella (GCT) and spindle cell oncocytoma (SCO) are posterior pituitary tumors (PPT). These lesions are non-neuroendocrine and low-grade neoplasms of the sellar region presenting with mass effect symptoms. Their clinical manifestation, hormonal profile and radiological findings are indistinguishable from non-functioning pituitary adenomas (NFPA). Recent data suggests that these three tumors could have a common origin from the pituicytes.

Aim: To evaluate a retrospective multicenter study of 15 patients with histological diagnosis of PPT.

Results: Our series included 6 pituicytomas, 3 GCT and 6 SCO. Mean age at diagnosis was 54.2 years old (range 30–74) and 11 patients were female. The most common symptoms of clinical presentation were visual defects (40%), amenorrhea (20%) and sever hyponatraemia (20%). One case had hypercortisolism symptoms. Hormonal assessment showed hyperprolactinemia (40%), hypopituitarism (33%) and ACTH dependent hypercortisolism in one patient. No patient had diabetes insipidus (DI). MRI showed sellar/suprasellar masses with median size of 24.5 mm (±10.3), chiasmatic compression in 46% and cavernous sinuses infiltration in 13% of the patients. Fourteen patients underwent surgery (one patient died before intervention and diagnosis was made by previously biopsy). In 10 patients transphenoidal approach was performed while craniotomy was chosen in 4 cases. Serious bleeding during surgical procedure occurred in 3 cases (20%) and one of them died due to hemorrhage in the early postsurgical period. After surgery 8 patients had hypopituitarism (61%) and 5 patients (38%) developed DI. Complete resection was achieved in 8 cases and residual tumor persisted in the remaining 5 patients. A second intervention was performed in 3 cases (20%). The pathological evaluation of pituitary specimen in the patient with Cushing’s disease, revealed a concomitant corticotropes hyperplasia and a GCT. Cushing’s disease persisted after three interventions in this patient, radiotherapy and adrenolytic agent were also prescribed.

Conclusion: PPT are usually misdiagnosed as NFPA because of their clinical and imaging characteristics. However, the behave more aggressive than NFPA and the perioperative complications such as intra-operative bleeding, hypopituitarism, DI and incomplete resection are common.